Control means for a fluid-powered device

ABSTRACT

Fluid control means, employing a pair of valving members, to automatically cycle the operation of the device. One valving member is translated in one direction, as the device is fluidcharged, to a point at which said one valving member opens fluid passages to a triggering chamber to fire the device. The second valving member holds the triggering chamber open to venting, to drain leak-through fluid, until the device is about to fire. Then, just prior to the firing, the first valving member opens passages to pressured fluid which drives the second valving member into closure of vent passages to halt the venting of the triggering chamber. Firing of the device returns the first valving member in the alternate direction for re-charging of the device.

United States Patent Ottestad July 9, 1974 CONTROL MEANS FOR AFLUID-POWERED DEVICE Primary ExaminerP aul E. Maslousky 75 Inventor:Jack B. Ottestad, La .lolla, Calif. Agent Murphy [73] Assignee: ImpulseProducts Corporation, San [57] ABSTRACT Diego, Calif.

7 Fluid control means, employing a pair of valving mem- Flled' 1972bers, to automatically cycle the operation of the de- 21 App]. No.:279,694

' vice. One valving member is translated in one direction, as the deviceis fluid-charged, to a point at which said one valving member opensfluid passages to a [52] US. Cl 91/224, 91/235, 991l//226782, triggeringchamber to fire the device. The Second 1 valving member holds thetriggering chamber open to [51] Int. Cl. F0lb 7/18, F011 /16 Venting todrain leak through fluid, until the device is [58] Field of Search91/268, 222, 321, 235, about to fim Then just prior to the firing, thefirst 91/224, 272 valving member opens passages to pressured fluid whichdrives the second valving member into closure [56] References and ofvent passages to halt the venting of the triggering UNITED STATESPATENTS chamber. Firing of the device returns the first valving 343,5696/1886 Couper 91/268 member in the a ternate direction for re-chargingof 1,157,924 10/1915 Christiansen 91/268 the device. 3,137,483 6/1964Zinkiewicz... 91/268 0 3,524,385 8/1970 Ottestad 91/235 10 Claims, 10Drawmg Flgul'es I8 68 A x E 14 PATENTEDJUL 91974 SHEET l 0F 4 FIG. 2

Pmmmm 9W SHEET 2 BF 1 FIG. 4

FIG. 5

FIG. M

A ur 7 1 CONTROL MEANS FOR A FLUID-POWERED DEVICE This inventionpertains to control means for fluid powered devices and in particular tosuch control means which effect automatic recycling of such devices.

In the prior art, expecially from my earlier US. Pat. No. 3,363,513issued Jan. 16, 1968, entitled Impact Ram, are disclosed means externalof the device for effecting manual recycling. In a subsequent US. Pat.No. 3,524,385, issued Aug. 18, 1970 for Control Means for venting fluidfrom said housing; comprising valving means within said housingoperative in response to an admittance of pressured fluid into saidhousing to cause a portion of said housing to become charged to apredetermined level with said pressured fluid, operative to hold saidtriggering chamber open to venting via said venting means, until saidpredetermined level is reached, and operative to close off saidtriggering chamber venting and to direct pressured fluid from saidhousing portion into said triggering chamber, when said predeterminedlevel is reached, to cause movement of said plunger.

A feature of this invention comprises fluid control means employing apair of valving members to automatically cycle theoperation of thedevice. One valving member is translated in one direction, as the deviceis fluid-charged, to a point at which said one valving member opensfluid passages to a triggering chamber to fire the-device. The secondvalving member holds the triggering chamber open to venting, to drainleakthrough fluid, until the device is about to fire. Then,

plunger is slidably disposed therewithin, the piston and hollow plungercooperating with an end of the device to define therewithin a chamberfor confining a gas. The housing is ported for admitting and ventingfluid, such as hydraulic fluid into and from the housing, and thehousing, piston and plunger cooperate to define both a charging chamberand a triggering chamber.

As described in my more recent US. Pat. No. 3,524,385, (cited herein)the hydraulic fluid is admitted to the charging chamber to cause thepiston to retract within the plunger to compress the gas. The triggeringchamber is provided for subsequently receiving the charge of pressuredhydraulic fluid to admit the pressure fluid to an end surface of theplunger, so that the device is fired by causing the plunger toaccelerate in a given direction. To insure proper and repetitive firingof the device, valving means is provided within the device eitherintegral with the piston, or separate therefrom, to hold the triggeringchamber closed off from venting until the device is fired. Subsequentlythe valving means automatically admits the fluid charge into thetriggering chamber for impingement thereof upon the plunger surface.Only thereafter, the valving means vents the triggering chamber. Insummary then, according to my earlier teaching, the device-recyclingvalving means hold the triggering chamber closed to venting all thewhile the device is being fluid-charged, and opens the triggeringchamber to venting only after the device has fired.

This prior teaching of my control means is reasonably effective.However, it necessitates stringent manufacturing control of mating partsto insure that there will not be a leakage of fluid intothe triggeringchamber which will cause a misfire, a precipitate firing, of the.

plunger. In the present invention I teach means for overcoming thislimitation, and make it possible for manufacturing tolerances, andclearances of the mating components to be met with relaxed standards. Itis an object of this invention, therefore, to teach control means for afluid-powered device, such as an impact ram or the like, wherein thedevice has a working plunger, and a'housing supporting the plunger formovement, said housing having a surface cooperating with a surface ofsaid plunger to define a triggering chamber therebetween, and includingmeans for admitting pressured fluid into said housing and means for justprior to the firing, the first valving member opens passages topressured fluid which drives the second valving member into closure ofvent passages to halt the venting of the triggering chamber. Firing ofthe device returns the first valving member in the alternate directionforre-charging of the device.

Further objects and features of this invention will become more apparentby reference to the following description taken in conjunction with theaccompanying figures, in which:

FIG. 1 is an axial cross-sectional view of a first embodiment of theinvention; & FIG. 1A is a detail thereof. FIG. 2 is a partialcross-sectional view taken from FIG. 1 showing thedevice in a firstoperative position;

FIG. 3 is a partial view corresponding to that of FIG. 2 showing thedevice in a second operative position;

FIG. 4 is an axial half cross-sectional view and half external view' ofan alternate embodiment of the invention;

FIGS. 5 and 4 depict details of the means which supply pressured fluidinto the end cap assembly for charging of the device (of FIG. 4); andmeans for draining the fluid from the device.

FIG. 6 is a partial, axial, half cross-sectional view and half externalview of the FIG. 4 embodiment valving arrangement which effectsrecycling of this embodiment of the device, according to the invention;and

- FIGS. 7-9 depict operational functioning of the seal In FIG. 1 isshown a fluid-powered device 10, the same being an impact ram, whichincorporates the control means 12 of the invention. The device 10comprises a housing 14 in which a hollow plunger 16 is slidablyreceived, the plunger confining therewithin a piston 18 which defines aninner chamber 20 of the plunger. The chamber 20 receives a charge ofgas, via a port 22 and fitting 24, for resiliently constraining thepiston 18 in the illustrated direction within the plunger 16. One end 26of the piston is matingly received by an orifice 28 which is carried byan orifice retainer 30. The retainer 30 has a surface 32 which defines atriggering surface for the plunger 16. This surface 32 cooperates withthe end cap assembly 34 of the device to define a triggering chamber 36.

The piston 18 has a probe 38 extending therefrom which makes asubstantially sealed, sliding fit within a bore 40 formed within a sealbase 42 which is coupled to the end cap assembly 34. An orifice seat 44is disposed between the seal base 42 and orifice 28. The seal base has arecess 46 in an end thereof to receive a poppet 48, the poppet andpiston probe 38 being concentrically assembled. Vent channels 50 and avent chamber 52 formed in the end cap assembly 34 open onto a vent port54 which communicates with a fluid reservoir (not shown). The poppet 48has a conical terminal 56 which opens or closes off the vent channels50, whereby the triggering chamber 36 is permitted to open onto thereservoir or is closed off from venting. The seal base 42 has a secondrecess 58 in which is received a skirt 60 of the poppet 48. An annularlimit stop member 61 is set within recess 46.

The seal base 62 has a pair of triggering ports 62 formed therethroughwhich open internally of the seal base, onto recess 58, and openexternally onto the triggering chamber 36. Finally, the piston probe 38is hollow substantially throughout the length thereof and has a pair oflateral ports 64 adjacent the terminal end thereof for purposes to beexplained hereafter.

As more fully described in my prior, cited patents, pressured hydraulicfluid is admitted by way of a housing fluid inlet port 66 to communicatewith a retum chamber 68 defined between the plunger 16 and the housing14 for subsequent admittance through a plunger fluid inlet port 70 andtherefrom into the charging chamber 72 of the device. The chargingchamber 72 is defined by the outer surface of piston end 26, andsurfacing presented by the seal base 43, the orifice seat 44 and theorifice 28.

It does occur that there is some leakage of hydraulic fluid between theorifice seat 44 and the orifice 28; this leakage fluid is free to ventthrough the vent channels 50, passing through the triggering chamber 36without causing a firing of the device 10. So also, there is leakagebetween the piston probe 38 and the seal base 42; this fluid too is freeto pass through the triggering ports 62 and triggering chamber 36,without effecting the operation of the plunger 16, and will drainthrough the vent chamber 52. This novel fail-safe provisioning proceedsfrom the inventive arrangement of the poppet and vent chamber surfaces,and fluid pressures operative there, and elsewhere in the device, asexplained below.

Poppet 48 is caused to withdraw from port 54, thus a precipitatebuild-up of fluid pressure in triggering chamber 36 cannot occur; themovement of poppet 48 into recess 58 holds the triggering chamber 36open to venting. It is hydraulic fluid pressure which opens port 54, andholds it open all the while that the charging chamber 72 is beingcharged with fluid. Leakage hydraulic fluid, the same being at somepressure level, upon reaching the triggering chamber 36, can only openport 54. In chamber 36, the minimal quantity of moderately pressuredleakage fluid cannot overcome the restraint of plunger 16, yet, poppet48 presents a considerable impingement surface, in its concial terminal56, and must yield, and move into recess 58. Accordingly, the poppet 48is always operative to hold the triggering chamber 36 open to ventingall the while that the chamber 72 is being charged.

In normal operation, the pressured hydraulic fluid admitted via port 66will cause the piston 18 to translate down through the plunger 16 tocompress the gas confined within chamber 20. The piston 18 continues tomove, as the chamber 72 is being charged, and all this while the poppet48 is displaced from the port 54 in the end cap assembly 34, to providefor free venting of the triggering chamber 36, as just described. Whenthe lateral ports 64 in the piston probe 38 just clear the lowermostsurface of the seal base 42, the pressured fluid in chamber 72 can passthrough these ports 64 and out the hollow end of the probe 38 to effecttwo results. For one, the pressured fluid impinging upon a dome-shapedsurface 74 of the poppet 48 causes the poppet to move into port 54 andclose off the vent chamber. Additionally, the pressure fluid is admittedthrough the triggering ports 62 into the triggering chamber 36.Consequently, the triggering surface 32 of the plunger 16 receives thepressured fluid, and the plunger is driven on its working stroke.

These operations are depicted in FIGS. 2 and 3. In FIG. 2 is shown thecharging of the chamber 72 and the partial translation of the piston 18within the plunger 16. It is to be noted that the poppet 48 is displacedfrom the poppet seat in port 54, and the triggering chamber r 36 isfully open to venting. In FIG. 3 the piston 18 has traveled most of itsfull distance; the lateral ports 64 have just cleared the lowermostsurfaces of the seal base 42, and the highly pressured fluid within thecharging chamber 72 can pass therethrough to seat the poppet 48 andclose off the venting of the triggering chamber 36, and impinge onsurface 32 to move the plunger 16 on its stroke.

FIG. 4 shows an alternate embodiment of the invention in which same orsimilar index numbers signify same or similar components. Thisembodiment is also incorporated in a device 10' having a housing 14' anda plunger 16 with an end cap assembly passage 78 for venting thepressure fluid from the device. FIGS. 5 and 4 illustrate the coupling ofa drainage pipe 80 for removing the fluid from the vent passage 78, andthe supply of pressured hydraulic fluid to a port 82 formed in the endcap assembly 34. A pipe 84, carries the fluid to port 82, and a shortchannel 86 conducts the fluid to chamber 76. Passage 78 opens onto avent port 54' which receives a poppet 48'.

In this embodiment it is the poppet 48' which has lateral ports 64 (onlyone is shown) for admitting the triggering fluid pressure into thetriggering chamber 36. The piston probe 38 in this embodiment is nothollow, neither is it drilled through with passageways. On the contrary,the poppet 48', the piston probe 38 and the seal base 42 each haverelieved surfaces 88, 90 and 92, respectively, formed therein, thesesurfaces being cooperative to define an annular passageway, about thepiston probe 38, to communicate the charging chamber 72 with the ports64 in the poppet 48' for admittance of the pressured fluid through thetriggering ports 62 (only one is shown) formed in the seal base 42' tothe triggering chamber 36. The piston probe 38', poppet 48 and seal base42 also have lands 96, 98 and 100, respectively, which cooperate toprevent the admit-- tance of the pressured fluid into the triggeringchamber 36' until the piston 18 has traveled a predetermined distancewithin the plunger 16'.

In this embodiment, as in that of FIG. 1, the poppet 48' is displacedfrom the vent port 54 in the end cap assembly 34 all the while that thedevice is charging. Again, this is to accommodate the venting ofleakthrough fluid which passes between the orifice 28 and the seal base42'; and between the piston probe 38 and the seal base 42 and poppet 48prior to the piston 18? having traveled its full required distance.Shortly after land 96 has cleared the land 100 at the bottom of the sealbase 42, the annular passageway is defined about the piston probe 38'and admits the fluid first to the poppet 48 to hold the poppet sealinglyagainst the seat of port 54, to prevent any further venting of thetriggering chamber 36. Then, also, the fluid further proceeds throughthe lateral ports 64 in the poppet 48' down through the seal basetriggering ports 62 into the triggering chamber 36'. There it' impingesupon the orifice 28 to cause the plunger to be driven on a workingstroke.

This second embodiment has additional features which greatly enhance thereliable operation thereof. For instance, the piston probe 38' has asecond land 104 which, in the furthermost travel of the piston 18 sealswith land 98 of the poppet 48. Accordingly, as land 96 of the probe 38clears the land 100 of the seal base 42, relieved surfaces 90 and 92cooperate to direct the pressured fluid against the skirt 106 of thepoppet 48'. This first, and positively, drives the poppet 48' intoclosure of port 54. Also, poppet 48 carries an annular shoulder 108which, following the firing of the plunger 16' (when the plungerproceeds to retract), receives the fluid pressure thereon from the fluidbeing evacuated from chamber 36' and this positively holds the poppet48' away from the port 54.

The retraction of the plunger 16 (or 16) and the reseating of the piston18' (or 18), for a recharging of the device( s), is effected in the samemanner as described in detail in my priorly-issued patents. Withreference, for example, to the embodiment depicted in FIGS. 1, 1A, 2, 3,and 7-9, the plunger retraction is explained. The plunger 16 will be inits furthermost extended position, and piston 18, under the urging ofgas in chamber 20, will have returned to mating engagement with theorifice 28 (as seen in FIG. 7). The poppet 48 will be unseated from port54, for two reasons. For one, the triggering charge, which both firedthe plunger 16 and forced the poppet 48 to its seat, is spent; also, asthe piston 18 rebounds under the force of the gas, it forces hydraulicfluid around the orifice seat 44 through the vent channels 50 to bear onthe conical terminal 56 of the poppet 48. Thus, the poppet opens theport 54, and remains displaced fromthe port until another triggeringforce seats it again.

Pressured hydraulic fluid admitted via port 66 again operates on theunder surfaces of the orifice 28 and retainer to proceed to retract theplunger 16. All this while, thelateral ports 64 in probe 38, and thetriggering ports 62 and triggering chamber 36 as well, are all open toventing. As the probe 38 never clears the seal base 42 it only withdrawsfar enough to allow ports 64 to open onto charging chamber 72 itcooperates with bore to prevent premature hydraulicfluid charging oftriggering chamber 36.

As discussed further on, in connection with FIGS. 7-9, the piston 18first seals with the orifice 28, as the plunger 16 continues to retract,and then the plunger 16 seals with the orifice seat 44. As the plunger16 is finally seating, becoming fully retracted, the piston 18 isdisplaced from the orifice 28; this is to expose an impingement surfaceof the piston 18 to cause it to yield to the incoming, pressuredhydraulic fluid and to become charged again for the next stroke.

To insure a continuous recycling of the devices 10 and 10', the depictedembodiments have features operative to prevent a high pressure stallfrom occuring. These features, with reference to FIGS. 1 and 8-10 fordevice 10, and FIG. 7 for device 10, are described in the followingparagraphs.

Seal base 42 (FIGS. 1, 7-9) has a pair of pins extending therefrom. Pins110 are disposed for contacting the head of piston 18, upon the returnof piston toward the seal base, and for holding the piston a specifieddistance away from orifice 28 as the orifice closes upon the orificeseat 44. This is necessary to be able to charge the device 10 for anon-following cycle, because of the geometry of the piston 18 and orifice28.

The gas in chamber 20 is operative against the full undersurface of thepiston 18. Thus, if only a minimal, annular surface of piston 18 isexposed for impingement of hydraulic fluid thereon, the hydraulic fluidpressure would have to be inordinately high to overcome the bias of thegas pressure before the piston 18 could proceed to translate downthrough the plunger 16. Therefore, a cycle stall would obtain, until thehydraulic pressure was sufficiently increased. Pins 110 avoid thisproblem, and yet they accommodate a necessary, reasonable effectivesealing-off of triggering chamber 36 from charging chamber 72 as theplunger 16 proceeds to seat in its retracted position.

As illustrated in FIG. 7, the piston 18 and plunger 16 are retractingfrom a preceeding firing of the device 10. A reasonably effective sealobtains at point A while both the piston 18 and plunger 16 move togethertoward the seal base 42.

In FIG. 8 is shown that operative progression where the following eventsproceed to occur: Pins 110 contact the head of piston 18, preventingfurther piston travel; seal point A proceeds to migrate away(downwardly) from its prior location; and a new, reasonably effectiveseal B proceeds to be joined between the orifice seat 44 and the orifice28. Seal B is first located only at the lowermost extremity of orificeseat 44; as the plunger 16 continues to seat, seal B grows in depthalong a short, axially-disposed, annular interface of seat 44 andorifice 28.

FIG. 9 shows the piston 9 held off, by pins 110, from closure againstorifice 28, providing access to the head of the piston 18 for thein-charging hydraulic fluid. Seal point A on piston 18 is displaced fromthe orifice 28, yet seal B is fully joined.

Device 10 (FIGS. 4 and 6) relies on the geometry of piston 18 and sealbase 42 to open the head of piston 18 to charging hydraulic fluid afterplunger 16 has initiated a sealing between triggering chamber 36' andcharging chamber 72'. Piston 118 has an annular shoulder 112 whichimpinges against the lowermost surface of seal base 42 to prevent aclosure of chamber 72' to the head of the piston. Yet, when the piston18 and plunger l6are retracted toward the seal base 42, a seal ismaintained at A. This seal opens, but only after another seal B iscommenced between the ori-' fice 28' and the seal base 42', upon theshoulder 112 engaging the seal base, and as the orifice 28 fully closesupon the seal base.

While I have described my invention in connection with specificembodiments, thereof it is to be clearly understood that this is doneonly by way of example, and not as a limitation to the scope of myinvention as set forth in the objects thereof, and in the appendedclaims.

I claim:

1. Control means for a fluid-powered device such as an impact ram or thelike wherein the device has a working plunger, and a housing supportingthe plunger for movement, said housing having a surface cooperating witha surface of said plunger to define a triggering chamber therebetween,and means for admitting pressured fluid into said housing and means forventing fluid from said housing; comprising:

valving means, within said housing, operative in response to anadmittance of pressured fluid into said housing to cause a portion ofsaid housing to become charged to a predetermined level with saidpressured fluid; wherein said fluid admitting means includes means foraddressing admitted fluid to a portion of said plunger to constrain saidplunger against movement; said valving means is further operative tohold said triggering chamber open to venting, via said venting means,until said predetermined level is reached, to prevent a fluid pressuringof said plunger surface which would overcome said plunger movementcontraint and induce premature plunger movement, and operative to closeoff said triggering chamber venting and to direct pressured fluid fromsaid housing portion into said triggering chamber, when saidpredetermined level is reached, to cause a fluid pressuring of saidchamber and plunger surface and a resultant, timely movement of saidplunger. 2. Control means for a fluid-powered device such as an impactram or the like wherein the device has a working plunger, and a housingsupporting the plunger for movement, said housing having a surfacecooperating with a surface of said plunger to define a triggeringchamber therebetween, and means for admitting pressured fluid into saidhousing and means for venting fluid from said housing; comprising:

valving means, within said housing, operative in response to anadmittance of pressured fluid into said housing to cause a portion ofsaid housing to become charged to a predetermined level with saidpressured fluid, operative to hold said triggering chamber open toventing, via said venting means, until said predetermined level isreached, and operative to close off said triggering chamber venting andto direct pressured fluid from said housing portion into said triggeringchamber, when said predetermined level is reached, to cause movement ofsaid plunger; wherein said valving means includes a wall member movablydisposed within said housing; and

means for resiliently and normaliy constraining said wall member in agiven direction relative to said housing portion; wherein said ventingmeans comprises a fluid conductive passageway open to venting at one endthereof, and opening onto said triggering chamber to another endthereof;

said valving means further includes closure means,

movably disposed within said passageway, to allow venting of saidchamber and for closing off chamber venting;

said closure means and said wall member each havepressured-fluid-impingement reaction surfaces;

said wall member reaction surfaces being disposed to receivehousing-admitted pressured fluid thereupon to effect a movement of saidwall member in a direction other than said given direction; and

said wall member has conduit means operative for conducting pressuredfluid from said housing portion to both said reaction surface of saidclosure means and to said triggering chamber, only upon said wall memberhaving moved a predetermined distance in said other direction, to causesaid closure means to close off said passageway to halt venting of saidchamber.

3. Control means, according to claim 2, wherein:

said wall member comprises a piston;

said conduit means comprises an elongated probe,

extending from and movable with said piston;

said housing has a bored-through seal base element fixedinterpositionally between said housing portion and said triggeringchamber;

said seal base element has at least one triggering port formedtherethrough which opens at opposite ends thereof internally of saidelement onto the bore formed therein, and externally of said elementonto said triggering chamber;

said bore of said element receives said probe therewithin;

said probe has a fluid-conductive passage formed therein which opens atone end thereof externally of said probe, at an location intermediatethe length of said probe, and which opens internally of said probe, atthe other end of said passage, at the terminal end of said probe; and

said passage communicates said housing portion both with said onetriggering port and said reaction surface of said closure means, onlyupon said piston having moved said predetermined distance.

4. Control means, according to claim 3, wherein:

said venting means passageway includes an annular venting chamber;

said closure means comprises a poppet;

said element cooperates with said housing to define said passagewaytherebetween;

said element slidably receives said poppet within said bore for movementof said poppet, relative to said element, into and out of said ventingchamber;

said venting chamber opens into a venting port formed in said housing;and

said poppet has a land formed thereon which obstnucts and opens saidport; and

said probe and said poppet are concentrically disposed within saidhousing.

5. Control means, according to claim 4, wherein:

said poppet has a recess centrally formed therewithin; and

said probe is received within said recess.

6. Control means, according to claim 5, wherein:

said other end of said passage of said probe is ori-- ented toward saidrecess.

7. Control means, according to claim 6, wherein:

walls of said recess define said reaction surfaces of said closuremeans.

8. Control means for a fluid-powered device such as an impact ram or thelike wherein the device has a working plunger, and a housing supportingthe plunger for movement, said housing having a surface cooperating witha surface of said plunger to define a triggering chamber therebetween,and means for admitting pressured fluid into said housing and means forventing fluid from said housing; comprising:

valving means, within said housing, operative in response to anadmittance of pressured fluid into said housing to cause a portion ofsaid housing to become charged to a predetermined level with saidpressured fluid operative to hold said triggering chamber open toventing, via said venting means, until said predetermined level isreached, and operative to close off said triggering chamber venting andto direct pressured fluid from said housing portion into said triggeringchamber, when said predetermined level is reached, to cause movement ofsaid plunger; wherein said valving means includes a wall member movablydisposed within said housing, and

means for resiliently and normally constraining said wall member in agiven direction relative to said housing portion; wherein said ventingmeans comprises a fluid-conductive passageway open to venting at one endthereof, and opening onto said triggering chamber at another endthereof;

said valving means further includes closure means movably disposedwithin said passageway to allow venting of said chamber and for closingoff chamber venting;

said closure means said said wall member each havingpressured-fluid-impingement reaction surfaces;

said wall member reaction surfaces being disposed to receivehousing-admitted pressured fluid thereupon to effect a movement of saidwall member in a direction other than said given direction; and

said wall member has probe means cooperative with said closure means andsaid housing to define a conduit for conducting pressured fluid fromsaid housing portion to both said reaction surface of said closure meansand to said triggering chamber, upon said wall member having moved apredetermined distance in said other direction, to cause said closuremeans to close off said passageway to halt venting of said chamber.

9. Control means for a fluid-powered device, wherein the device has amovable, working plunger, means supporting the plunger for movement,said plunger having a fluid-impingement triggering surface, saidsupporting means and said surface cooperatively defining a triggeringchamber therebetween, means for admitting fluid into said chamber forcausing impingement of fluid on said surface to move said plunger, andmeans for venting fluid from said chamber, said admitting meansincluding means for storing an increasingly pressured charge of fluid;comprising:

valving means, interposed between said chamber and said admitting andventing means, operative to communicate said chamber with said ventingmeans only until stored, pressure fluid is conducted to said chamber,and operative in cooperation with said admitting means to conductstored, pressured fluid from said admitting means to said chamber, onlywhen said stored fluid achieves a predeterminedpressure level; whereinsaid admitting means further includes means for addressing admittedfluid to a portion of said plunger to constrain said plunger againstmovement until said stored fluid achieves said predetermined level.

10. A fluid-powered device, such as an impact ram or the like,comprising:

a movable, working plunger;

means supporting the plunger for movement; I

said plunger having a fluid-impingement triggering surface;

said supporting means and said surface cooperatively defining atriggering chamber therebetween;

means for admitting fluid into said chamber for causing impingement offluid on said surface to move said plunger;

means for venting fluid from said chamber; and

valving means, interposed between said chamber and said admitting andventing means, operative to communicate said chamber with said ventingmeans only until said admitting means conducts fluid into said chamber;wherein said admitting means includes means for storing an increasinglypressured charge of fluid, means cooperative with said valving means forconducting stored, pressured fluid to said chamber only when saidstored, pressured fluid achieves a predetermined level, and means foraddressing admitted fluid to a portion of said plunger to constrain saidplunger against movement until said stored fluid achieves saidpredetermined level.

1. Control means for a fluid-powered device such as an impact ram or thelike wherein the device has a working plunger, and a housing supportingthe plunger for movement, said housing having a surface cooperating witha surface of said plunger to define a triggering chamber therebetween,and means for admitting pressured fluid into said housing and means forventing fluid from said housing; comprising: valving means, within saidhousing, operative in response to an admittance of pressured fluid intosaid housing to cause a portion of said housing to become charged to apredetermined level with said pressured fluid; wherein said fluidadmitting means includes means for addressing admitted fluid to aportion of said plunger to constrain said plunger against movement; saidvalving means is further operative to hold said triggering chamber opento venting, via said venting means, until said predetermined level isreached, to prevent a fluid pressuring of said plunger surface whichwould overcome said plunger movement contraint and induce prematureplunger movement, and operative to close off said triggering chamberventing and to direct pressured fluid from said housing portion intosaid triggering chamber, when said predetermined level is Reached, tocause a fluid pressuring of said chamber and plunger surface and aresultant, timely movement of said plunger.
 2. Control means for afluid-powered device such as an impact ram or the like wherein thedevice has a working plunger, and a housing supporting the plunger formovement, said housing having a surface cooperating with a surface ofsaid plunger to define a triggering chamber therebetween, and means foradmitting pressured fluid into said housing and means for venting fluidfrom said housing; comprising: valving means, within said housing,operative in response to an admittance of pressured fluid into saidhousing to cause a portion of said housing to become charged to apredetermined level with said pressured fluid, operative to hold saidtriggering chamber open to venting, via said venting means, until saidpredetermined level is reached, and operative to close off saidtriggering chamber venting and to direct pressured fluid from saidhousing portion into said triggering chamber, when said predeterminedlevel is reached, to cause movement of said plunger; wherein saidvalving means includes a wall member movably disposed within saidhousing; and means for resiliently and normally constraining said wallmember in a given direction relative to said housing portion; whereinsaid venting means comprises a fluid-conductive passageway open toventing at one end thereof, and opening onto said triggering chamber toanother end thereof; said valving means further includes closure means,movably disposed within said passageway, to allow venting of saidchamber and for closing off chamber venting; said closure means and saidwall member each have pressured-fluid-impingement reaction surfaces;said wall member reaction surfaces being disposed to receivehousing-admitted pressured fluid thereupon to effect a movement of saidwall member in a direction other than said given direction; and saidwall member has conduit means operative for conducting pressured fluidfrom said housing portion to both said reaction surface of said closuremeans and to said triggering chamber, only upon said wall member havingmoved a predetermined distance in said other direction, to cause saidclosure means to close off said passageway to halt venting of saidchamber.
 3. Control means, according to claim 2, wherein: said wallmember comprises a piston; said conduit means comprises an elongatedprobe, extending from and movable with said piston; said housing has abored-through seal base element fixed interpositionally between saidhousing portion and said triggering chamber; said seal base element hasat least one triggering port formed therethrough which opens at oppositeends thereof internally of said element onto the bore formed therein,and externally of said element onto said triggering chamber; said boreof said element receives said probe therewithin; said probe has afluid-conductive passage formed therein which opens at one end thereofexternally of said probe, at an location intermediate the length of saidprobe, and which opens internally of said probe, at the other end ofsaid passage, at the terminal end of said probe; and said passagecommunicates said housing portion both with said one triggering port andsaid reaction surface of said closure means, only upon said pistonhaving moved said predetermined distance.
 4. Control means, according toclaim 3, wherein: said venting means passageway includes an annularventing chamber; said closure means comprises a poppet; said elementcooperates with said housing to define said passageway therebetween;said element slidably receives said poppet within said bore for movementof said poppet, relative to said element, into and out of said ventingchamber; said venting chamber opens into a venting port formed in saidhousing; and said poppet has a land formed thereon which obstructs andopens said port; and said probe and said poppet are concentricallydisposed within said housing.
 5. Control means, according to claim 4,wherein: said poppet has a recess centrally formed therewithin; and saidprobe is received within said recess.
 6. Control means, according toclaim 5, wherein: said other end of said passage of said probe isoriented toward said recess.
 7. Control means, according to claim 6,wherein: walls of said recess define said reaction surfaces of saidclosure means.
 8. Control means for a fluid-powered device such as animpact ram or the like wherein the device has a working plunger, and ahousing supporting the plunger for movement, said housing having asurface cooperating with a surface of said plunger to define atriggering chamber therebetween, and means for admitting pressured fluidinto said housing and means for venting fluid from said housing;comprising: valving means, within said housing, operative in response toan admittance of pressured fluid into said housing to cause a portion ofsaid housing to become charged to a predetermined level with saidpressured fluid operative to hold said triggering chamber open toventing, via said venting means, until said predetermined level isreached, and operative to close off said triggering chamber venting andto direct pressured fluid from said housing portion into said triggeringchamber, when said predetermined level is reached, to cause movement ofsaid plunger; wherein said valving means includes a wall member movablydisposed within said housing, and means for resiliently and normallyconstraining said wall member in a given direction relative to saidhousing portion; wherein said venting means comprises a fluid-conductivepassageway open to venting at one end thereof, and opening onto saidtriggering chamber at another end thereof; said valving means furtherincludes closure means movably disposed within said passageway to allowventing of said chamber and for closing off chamber venting; saidclosure means said said wall member each havingpressured-fluid-impingement reaction surfaces; said wall member reactionsurfaces being disposed to receive housing-admitted pressured fluidthereupon to effect a movement of said wall member in a direction otherthan said given direction; and said wall member has probe meanscooperative with said closure means and said housing to define a conduitfor conducting pressured fluid from said housing portion to both saidreaction surface of said closure means and to said triggering chamber,upon said wall member having moved a predetermined distance in saidother direction, to cause said closure means to close off saidpassageway to halt venting of said chamber.
 9. Control means for afluid-powered device, wherein the device has a movable, working plunger,means supporting the plunger for movement, said plunger having afluid-impingement triggering surface, said supporting means and saidsurface cooperatively defining a triggering chamber therebetween, meansfor admitting fluid into said chamber for causing impingement of fluidon said surface to move said plunger, and means for venting fluid fromsaid chamber, said admitting means including means for storing anincreasingly pressured charge of fluid; comprising: valving means,interposed between said chamber and said admitting and venting means,operative to communicate said chamber with said venting means only untilstored, pressure fluid is conducted to said chamber, and operative incooperation with said admitting means to conduct stored, pressured fluidfrom said admitting means to said chamber, only when said stored fluidachieves a predetermined pressure level; wherein said admitting meansfurther includes means for addressing admitted fluid to a portion ofsaid plunger to constrain said plunger against movement until saidstored fluid achieves said predetermined level.
 10. A fluid-powereddevice, such as an impact ram or the likE, comprising: a movable,working plunger; means supporting the plunger for movement; said plungerhaving a fluid-impingement triggering surface; said supporting means andsaid surface cooperatively defining a triggering chamber therebetween;means for admitting fluid into said chamber for causing impingement offluid on said surface to move said plunger; means for venting fluid fromsaid chamber; and valving means, interposed between said chamber andsaid admitting and venting means, operative to communicate said chamberwith said venting means only until said admitting means conducts fluidinto said chamber; wherein said admitting means includes means forstoring an increasingly pressured charge of fluid, means cooperativewith said valving means for conducting stored, pressured fluid to saidchamber only when said stored, pressured fluid achieves a predeterminedlevel, and means for addressing admitted fluid to a portion of saidplunger to constrain said plunger against movement until said storedfluid achieves said predetermined level.